Fuel cost depends on three inputs: distance, fuel consumption, and unit price. A route estimate does not supply a guaranteed pump price or actual economy.
If you are looking for a MapQuest Gas Calculator, start with the distance of the journey you intend to drive. Then combine that distance with the vehicle’s expected fuel economy and an assumed price. The calculation is straightforward; the uncertainty usually comes from those inputs rather than from the arithmetic.
The estimator below is our own tool, not an official MapQuest calculator. It accepts a distance you enter manually, including a distance taken from a route planner. It does not retrieve live fuel prices, identify your vehicle, or calculate tolls. Example prices on this page are illustrative and should be replaced with figures relevant to your trip.
Estimate your fuel cost
Example inputs are prefilled. Enter your own distance, consumption and price; no live prices are fetched.
10.00 US gallons for 300.00 miles
Fuel only. Excludes tolls, parking and other trip costs. US gallons only in MPG mode. If your return differs, include it in the entered distance and leave the return option off.
Calculate fuel from miles and MPG
With miles and US miles per gallon, divide the trip distance by the expected MPG. That gives the number of US gallons. Multiply the gallons by the price per US gallon to estimate fuel cost. Keep the units consistent: an imperial gallon is different from a US gallon, so imperial MPG should not be entered as US MPG.
For a worked example, a 300-mile journey at 30 US MPG uses an estimated 10 US gallons. At an assumed $3.60 per gallon, the fuel estimate is $36. If 300 miles describes only the outward journey and the return is equally long, the 600-mile total produces $72 under the same assumptions.
Fuel cost = (distance in miles ÷ US MPG) × price per US gallon
Use litres per 100 kilometres correctly
With metric consumption, multiply kilometres by litres per 100 kilometres, then divide by 100. Multiply that result by the price per litre. A lower L/100 km figure represents lower consumption, while a higher MPG figure represents better economy. Mixing those two conventions reverses the meaning of the input.
For example, 450 kilometres at 7.2 L/100 km uses an estimated 32.4 litres. With an assumed price of 1.70 currency units per litre, the cost is 55.08 currency units. The calculator uses the same currency as the price you enter; it does not convert currencies or fetch exchange rates.
Fuel cost = (distance in km × L/100 km ÷ 100) × price per litre
Choose inputs that resemble the trip
Use the complete route distance, including planned detours and the return where relevant. Choose a consumption figure that reflects the type of drive rather than assuming a best-case headline figure. Congestion, speed, load, terrain, and weather can change actual fuel use, so an estimate should not be treated as a measurement.
If you are uncertain, calculate two scenarios. Keep the distance and price fixed, then enter a less favorable consumption figure for the second result. The difference shows how sensitive the budget is to fuel economy. Label this as a scenario range rather than a confidence interval based on measured trip data.
Check whether a cheaper fuel stop saves anything
Suppose a station offers an assumed saving of $0.10 per gallon and you expect to buy 10 gallons. The gross saving is $1. A six-mile detour at 30 US MPG uses 0.2 gallons; at an assumed $3.60 per gallon, that costs $0.72. Only $0.28 remains before considering your time.
This example is intentionally small because a lower displayed price can hide an inconvenient journey. Compare the amount you will actually buy with the full detour, including the return to your route. A stop already on the way is a different decision from one that requires extra driving.
Keep fuel separate from the total trip budget
Fuel is only one part of a road trip’s cost. Add parking, tolls, accommodation, and other spending separately if you need a whole-trip budget. Do not call the calculator’s fuel result the cost of owning or operating the vehicle: it excludes maintenance, depreciation, insurance, and other expenses.
For an electric vehicle, use a separate calculation based on energy consumption and charging price. Converting an electric consumption figure into the MPG field would give a misleading result. Whichever method you use, retain the inputs alongside the estimate so you can revise it when the plan changes.
Common questions
Does this calculator show current gas prices?
No. You supply the price. The default numbers and worked examples are assumptions for demonstrating the calculation, not local prices or a forecast.
Does the fuel estimate include a return journey?
Only when the entered distance includes it or you choose the same-distance return option. If the return route is different, enter the combined distance of both legs instead.
The formulas, assumptions, and worked examples are explained on this page. These are independent planning estimates, not official MapQuest tools or measured travel results.